Facts & Figures about all things Berchtesgaden salt mine

In salt mining, a drilling mud sink work is a hollow area that is opened up for the extraction of brine in wet mining. It is filled with fresh water. The water has the task of dissolving out the water-soluble components, i.e. also the salt, from the rock mass on the ceiling and walls. The insoluble components of the rock sink to the bottom and settle on the ground. The cavity increases in size due to the constant influx of fresh water. This process is repeated until a 3,500 to 5,000 cubic metre so-called initial cavity is completed. Only then does the actual brine extraction begin.

Samples are taken to determine the required minimum salt content in the rock. The boreholes for this are being drilled to a depth of 400 metres below the mining level.

In Berchtesgaden, the salt is extracted in the so-called "wet mining". In the process, fresh water is introduced into the rock, which dissolves the salt out of the mixed rock. The result is brine, i.e. a concentrated salt solution with a salt content of 26.5 %. The principle of wet mining has not changed to this day. The brine is extracted in so-called drilling mud plants.

Brine is understood to be a saturated salt solution, i.e. salt water, which contains the maximum possible proportion of 26.5 % salt. In Berchtesgaden, brine is created by channeling fresh water into the mountains, where it dissolves the salt out of the rock. The Berchtesgaden brine is pumped to the Bad Reichenhall salt works and processed into salt there.

Continuous brine extraction begins when the ceiling area of the cavity has reached approximately 3,000 m². Every day, about 1 cm of rock is loosened from the slab surface. At a mining height of 100 m, a drilling mud sink work can be used for around 30 years. During this time we produce over 1.3 million cubic metres of saturated brine.